262 Dr Samuel George Morton on the 
Observations on the Size of the Brain in various Races and 
Families of Man. By SAMUEL GEORGE Morton, M.D., 
Author of Crania Americana, &c., &c. 
[have great pleasure in submitting to the Academy* the re- 
sults of the internal measurements of 623 human crania, 
made with a view to ascertain the relative size of the brain 
in various races and families of Man. 
These measurements have been made by the process in- 
vented by my friend, Mr J. 8. Phillips, and described in my 
Crania Americana, p. 253, merely substituting leaden shot, 
one-eighth of an inch in diameter, in place of the white mus- 
tard-seed originally used. I thus obtain the absolute capacity 
of the cranium, or bulk of the brain, in cubic inches; and the 
results are annexed in all those instances in which I have 
had leisure to put this revised mode of measurement in prac- 
tice. I have restricted it, at least for the purpose of my in- 
ferential conclusions, to the crania of persons of sixteen years 
of age and upwards, at which period the brain is believed to 
possess the adult size. Under this age, the capacity mea- 
surement has only been resorted to for the purpose of colla- 
teral comparison ; nor can I avoid expressing my satisfaction 
at the singular accuracy of this method, since a skull of an 
hundred cubic inches, if measured any number of times with 
reasonable care, will not vary a single cubic inch. 
All these measurements have been made with my own 
hands. I at one time employed a person to assist me; but, 
having detected some errors in his measurements, I have 
been at the pains to revise all that part of the series that 
had not been previously measured by myself. I can now, 
therefore, vouch for the accuracy of these multitudinous 
data, which I cannot but regard as a novel and important 
contribution to Ethnological science. 
I am now engaged in a memoir which will embrace in de- 
tail the conclusions that result from these data; and, mean- 
while, I submit the following tabular view of the prominent 
facts. 
* Academy of Natural Sciences of Philadelphia. 
